E·pis·tle n.
 1. A writing directed or sent to a person or persons; a written communication; a letter; -- applied usually to formal, didactic, or elegant letters.
    A madman's epistles are no gospels.   --Shak.
 2. Eccl. One of the letters in the New Testament which were addressed to their Christian brethren by Apostles.
 Epistle side, the right side of an altar or church to a person looking from the nave toward the chancel.
    One sees the pulpit on the epistle side.   --R. Browning.